given the time interval during which that distance is traveled, the ratio, quick boom, that's your speeeed. your distance--your ratio of distance to time may change. sometimes, you might cover a lot of distance in a short time, and other times a longer distance in a longer time, so it may change. so strictly speaking, we say your average speed is how far you go divided by how long the time it takes. i put that little bar there to mean average, average speed. knowing that, we can turn around and say this: if i tell you that my average speed is 60 kilometers per hour and i travel in a half hour, can you tell me how far i've gone? check your neighbor. see if your neighbor be knowing. what's the answer, gang? 30 kilometers. 30 kilometers. how did you get it? 60-- you can turn this around. if this is true, then the distance you travel is simply equal to the average speed multiplied by the time you travel. and so this, a relationship for how far, and this, a relationship for how fast, at least the average of how fast. your average speed and the distance you travel and you know the average speed